Differing processing tools accept a workpiece and perform different processing steps depending on the type of tool. One type of a processing tool is an ion processing tool where a workpiece is treated with ions. An ion processing tool may include a plasma assisted doping (PLAD) tool or a beamline tool. A PLAD tool includes a process chamber where plasma is generated. One or more workpieces are positioned in the process chamber and biased to attract ions from the plasma. The ions may provide for precise material modification to the workpiece. The workpiece may include but not be limited to, magnetic disks, semiconductor wafers, flat panels, solar panels, and polymer substrates. A beamline tool includes an ion source and an extraction electrode assembly to extract a well defined ion beam from the ion source. One or more beamline components known in the art may control, modify, and direct the ion beam with desired characteristics towards a surface of a workpiece. The workpiece for the beamline tool may also include, but not be limited to, magnetic disks, semiconductor wafers, flat panels, solar panels, and polymer substrates. The ion beam may be distributed across a surface of the workpiece by ion beam movement, workpiece movement, or a combination of the two.
Many workpieces to be treated by such process tools are single sided workpieces in that there is only one side or surface of the workpiece subject to treatment. For example, the front surface of a conventional semiconductor wafer is treated with ions but the rear surface is not. However, some workpieces are dual sided workpieces that have front and opposing rear sides to be treated. For example, a magnetic disk used in a conventional hard disk drive may require ion treatment on both sides of the disk.
Conventional wafer handling equipment in an ion processing tool accepts a dual sided workpiece for processing and treats only a first side of the workpiece. If a second opposing side of the same workpiece also needs to be treated, it is removed from the ion processing tool which is typically under vacuum while processing. Once removed from the tool and the vacuum condition, the workpiece would then need to be reoriented, and then inserted back into the ion processing tool with its second opposing side now positioned for treatment. One drawback with this conventional equipment and method is the substantial time to perform the removal and reinsertion steps. This additional time negatively impacts throughput performance or the number of workpieces that can be processed over a given time period. Another drawback is that these removal and reinsertion steps necessarily involve workpiece handling operations which is an inherent factor in reliability of the entire processing operation.
Accordingly, there is a need in the art for improved dual sided workpiece handling that overcomes the above-described inadequacies and shortcomings.